Surveillance Group Weekly Report 2/7/2007

RECAP

Detection of People Carrying Objects Using Silhouettes Larry Davis . PAMI, 2000 and Computer Vision and Image Understanding, 2001 Silhouettes if humans are typically close to symmetric. We can use symmetry analysis to help us detect when a person is carrying an object. Davis et al . PAMI, 2000 Mainly true while standing, walking or runing Davis et al . PAMI, 2000

Review

Symmetry Analysis Every pixel of a blob is classified as symmetric or asymmetric : if X = Symmetric Asymmetric Otherwise We can analyise how symmetric this blob is.

Symmetry Analysis Person is carrying object if : Too Simple!

Omar’s Approach Recurrent Motion Image (RMI) Omar Javed and Mubarak Shah, “Tracking And Object Classification For Automated Surveillance”, 2002. Recurrent Motion Image (RMI) Binary silhouette image Binary image indicating areas of motion High RMI values indicate areas where motion occurs repeatedly

Testing Output blobs Frame: 50 51 52 53

Testing (Continued) Recurrent Motion Image: Red areas indicate an RMI above a threshold Blue areas indicate low RMI values

Testing (Continued) if X = Symmetric Asymmetric Otherwise Perform PCA to find major axis (using low RMI areas) Perform symmetry analysis disregarding high RMI areas (Red) if X = Symmetric Asymmetric Otherwise Asymmetric areas are marked in yellow:

PETS 2006 Benchmark Data Dataset S1 (Take 1-C): People carrying luggage People leaving luggage http://www.cvg.rdg.ac.uk/PETS2006/